Shaving apparatus



K. W. CHAUN SHAVING APPARATUS May 11, 1954 mug Filed Sept. 8, 1950 mmml having curved Patented May 11, 1954 2,677,885 SHAVIN G APPARATUS Kenneth W. Chaun, Kowloontong,

China Hong Kong,

Application September 8, 1950, Serial N 0. 183,783

1 Claim.

This invention relates to shaving apparatus and more particularly to motor-driven devices having a rotary cutter and stationary shear cap cooperating therewith.

According to the ing apparatus of the noted type is provided with further provided at its central portion with a plurality of small apertures cooperating with the innermost ends of the rotary knife cutting edges.

It is therefore an object of this invention to provide a shaving apparatus of the rotary type cutting edges to improve the efficiency thereof.

It is a further object of vide with a rotary knife.

It is a further object of this invention to provide a shaving apparatus having a stationary shear cap provided with a toric surface at its outer periphery whereby to increase the efliciency and ease of operation of the apparatus.

Further objects and advantages will appear as the description proceeds in connection with the accompanying drawings wherein:

Figure 1 is an axial sectional view of a portion of a motor-driven shaving apparatus incorporating the present invention;

Figure 2 is a top plan view of the shear cap of Fig. 1;

Figure 3 is a top plan view of the rotary knife of Figure 1; and

Figure 4 is an axial sectional view of an attachment.

Apparatus incorporating the present invention may include a body member I of suitable plastic or other material constructed to house a suitable motor or source of power nalled in bushing 3 in the 4 is attached to an end of the housing and permanently amxed thereto. The cup 4 is provided with an upstanding peripheral flange 5 and a bothaving a shaft 2 jourhousing. A metal cup tom portion 6 abutting the end of the body memcup member and a depending portion imbedded in the material of the body member I. The boss or hearing 1 is axially aligned with the motor an axially extending tongue portion I0 of the shaft 2 to effect driving engagement between the shaft 2 and member 8. A spring I I, housed within the member 8, acts to normally urge the element outwardly away from the shaft 2.

A shear cap I2, preferably of thin sheet metal, is provided with a depending flange I 3 and an annular outwardly extending flange portion I4. The cap and flanges are so dimensioned that the flange I3 fits quite snugly within the upstanding flange portion 5 of the cup 4. The flange A retaining member I5, of generally cylindrical shape, is provided with an inwardly extending flange I6 adjacent its upper edge, which flange is arranged to bear upon the uppermost face of the flange I 4 of cap I 2. The member I5 is internally screw threaded, as at IT, and screw threads on the body member I to thereby clamp the shear cap I2 in assembled relationship to the cup member 4. The retaining member I5 may also be provided with a flange portion I8 which may 'be externally knurled as at I9, to facilitate ready manual manipulation for removal or replacement of the cap I2.

A rotary knife 20 is provided with a driving disc 2| which is adapted to be drivingly engaged by thedriving member 8 previously described. To this end disc 2| is provided a pair of openings extending vertically therethrough, adapted to receive driving bars or the like 22 carried by and axially projecting from the driving member 8. The bars 22 are of slightly lesser diameter than the openings in disc 2| to permit limited tilting movement of rotary knife 26 relative to driving member 8. A central projecting boss 23 is carried by the driving member 8 and engages the midportion of element 2| of knife 20 to transmit axial pressure from spring I i to the knife 20 to retain the latter in firm sliding engagement with. the cap I2. The knife 20 is provided with generally radially and axially extending blade portions 24 having a surface curved to a shape complemen- 3 tary to the inner surface of the shear cap i2. As is apparent, the knife 20 rotates on an axis generally normal to the cap l2.

Referring now to Figure 2, in addition to Figure 1, it will be seen that the shear cap 12 has a central circular portion, in the illustrated embodiment generally planar in shape, a depending fiange portion i3 and a smoothly curved crest portion 25. The crest portion 25 may be also defined as a generally toric surface in that it is similar in shape to a portion of the surface of a torus. The shear cap 12 is provided with a plurality of elongated slots 26 extending outwardly across the curved crest portion and into the central portion of the cap. As clearly seen in Figure 2, the slots 26 are curved to a somewhat lunar or crescent shape and the edges of the slots define cutting edges adaptable to cooperate with the rotary knife. During operation of the apparatus, the knife rotates in a clockwise direction relative to the cap [2 as seen in Figure 2 and the righthand edge of the slots 26 appearing at the top of the figure constitute the usable cutting edges and it will be noted that these edges are concave in a rearward direction,

that is, concave when viewed from an approaching knife blade. It is to be further noted that a radial chord may simultaneously intersect any one of the slots 26 at two different places, that is, at the inner and outer ends of the slots 26. I

The central portion of the shear cap is provided with a plurality of small apertures 21 for a purpose to be later described.

Figure 3, showing a plan view of the rotary knife 29, shows the knife as it would appear be- 1 low the cap 12 when. viewed in the same direction as Figure 2. As can be seen, the knife comprises a plurality of generally radially and axially extending blades 25. Each blade 24 defines a leading cutting edge 28 and each cutting edge is concave forwardly, that is, each cutting edge is concave when viewed from a shear cap slot being approached by the blade. The cutting edges 28 of the rotary knife are of sufficient length to extend from the outermost ends of the slots 26 to an inner position underlying the central portion of the shear cap inwardly of the plurality of openings 21.

The dotted outline one relative position of a slot cap and the cutting edge 28 of an adjacent knife blade 24. As can be readily seen, the concavity of the cutting edges 28 is such that a radial chord can simultaneously intersect any cutting edge 28 at two different points. Thus the cutting edges 28 will cross the inner and outer ends of the cutting edges defined by slots 26 while the midportions thereof remain substantially separated. Upon rotation of the knife 20 in the direction of the arrow of Figure 3, the points of intersection of the cutting edges will obviously approach each other and coincide substantially at the midportions of the slots 26. This point of coincidence lies intermediate the peripheral edges of the curved crest or toric surface 25 and provides an arrangement facilitating entry of relatively long hair into the slots 26 as the apparatus is being moved over the skin of a user in the usual manner. As the ends of such relatively long hairs enter the slots, the cutting edges engage such hair at a point substantially spaced from the users skin and since the hair is thus trapped between the approaching intersections of the cutting edges, it will be readily sheared, rather than deflected.

26' in Figure 3 illustrates 26 of the shear The apertures 21 may be employed in such manner as to receive hair ends, which will be sheared by rotation of the rotary knife in a wellknown manner.

While the central portion of the shear cap has been shown and described as substantially planar, it will be understood that the invention is not restricted to such an arrangement. The central portion of the cap 12 could readily be made convex outwardly to any desired degree and would operate with equal facility and efiiciency. While the rotary knife is shown as comprising a single integral structure, it will be readily apparent that the blades 24 and the driving element 2| may be formed as separate parts if desired and joined together in any suitable manner.

Figure 4 illustrates a dental attachment for the shaving apparatus of Figure 1. As previously described, the shear cap 25 and rotary knife 20 may be removed from the apparatus of Figure 1 by unscrewing the holding member IS. The attachment of Figure 4 comprises a cup element 46 of an outer diameter the same as the outer diameter of the shear cap 25 and having an outwardly extending flange 42 corresponding to the flange I4 of Figure 1. The cup 40 has a central upstanding boss 44 provided with a bronze or the like bushing 46. A shaft 48 is journalled in the bushing 48 and has an enlarged head 50 at its lower end provided with openings 52 corre-- sponding to the openings of the knife 20 adapted to receive the bars 22. The shaft 48 is not only rotatable in the bushing 46 but is longitudinally slidable therein also. At its outermost end the shaft 48 may be provided with a threaded socket 54 to removably receive a suitable dental brush or the like 56.

In use, the cap 40 is substituted for the shear cap 25 of Figure l and the openings 52 in the head 52 will embrace the bars 22 of the driving element 8. Such substitution having been made, it will be readily apparent that the dental brush 56 may be employed in a well-known manner to polish or otherwise treat the users teeth.

The attachment of Figure 4 thus increases the utility of the apparatus of Figure 1 and enables a single power source to be employed for the disclosed different purposes.

While a single specific embodiment of the invention has been shown and described herein, it is to be understood that the invention is not limited thereto, but encompasses all modifications falling fairly within the scope of the appended claim.

I claim:

In a shaving apparatus, a sheet metal shear cap defining an entire end portion of said apparatus comprising a substantially flat circular central portion and a peripheral axially extending flange portion, said central and flange portions being joined by a smoothly curved crest portion of substantial radial and axial extent, curved slots through said cap defining cutting edges extending across said crest portion and into said central portion, said cutting edges being concave in a peripheral direction with the bottom of the concavity lying substantially centrally of said crest portion, a rotary knife adapted to rotate about theaxis of said central portion and in sliding contact with the inner face of said cap, said knife having a curved blade having a leading edge defining a cutting edge substantially coincident with the inner surface of said cap, the cutting edges of said cap and knife being so relatively curved that inner and outer portions of the cutting edge of said knife simultaneously References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 935,137 Abeyta Sept.'28, 1909 1,719,140 Sanders July 2, 1929 Number Number 

